Vania



(No Model.)

H. N. POTTER. CIRCUIT INTERRUPTER FOR ALTBRNATING ELECTRIC CURRBNTS.

FIG.+.

Patented Mar. 5, 1895.

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UNITED STATES PATENT OFFICE.

HENRY NOEL POTTER, OF ALLEGHENY, ASSIGNOR TO THE WVESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, OF PITTSBURG, PENNSYL- VANIA.

CIRCUIT-INTERRUPTER FOR ALTERNATING ELECTRIC CURRENTS.

SPECIFICATION forming part of Letters Patent No. 535,077, dated March 5, I 895.

Application filed February 28, l. 894- Serial No. 501,769. (No model.)

To all whom it may concern: and the width of the gaps used in this case Be it known that I, HENRY NOEL POTTER, are dependent upon the voltage of the current a citizen of the United States, residing in which is interrupted. \Vhere, however, the Allegheny, in the county of Allegheny and electro-motive force and current are not in 5 State of Pennsylvania, have invented a new phase or step with each other, the use of nonand useful Improvement in Circuit-Interruparcing metal is insufiicient to prevent the forters for Alternating Electric Currents, (Case mation of arcs, and hitherto, no means has No. 582,) of which the following is a specilibeen found whereby the effectof the non-arccation. ing metal could be obtained in such cases. I 6o Myinvention relates to means forswitching have discovered that, if one or more of the or breaking alternating currents with safety, gaps between non-arcing metal parts used in without the use of auxiliary devices dependthe production ofacircuitrupturebe sh uuted ent upon the formation of an are for rupture by a resistance or capacity varying with the of the same, or of secondary mechanical deamperage of the current to be ruptured, all 65 vices for use in connection with the switch. the advantages of the non-arcing metal may here alternating currents of high potenbe obtained, even where the currentand electial are employed, any attempt to break the tro-motive force are not in phase with each circuit is attended with dangerous and perother. My invention contemplates an effisistent arcs, forthe rupture of which many cient embodiment ofthis principle in the pro- 70 attempts have been made, but all devices for du'ction of circuit interrupting devices.

this purpose have contemplated devices exte- My invention is illustrated in the accomparior to the switch proper, working either menying drawings, wherein chanically or magnetically to rupture by some Figure 1 represents a double jaw switch of means the arcs once formed. It is the object an old form, showing the mode of operation 7 zgof my invention to provide means whereby of a switch which is available for breaking the arc may be prevented from forming, and circuits wherein the current and potential are my invention therefore does not contemplate in step, but of no use where these are out of the use of means for rupturing an are, but for step. Figs. 2, 3 and 4 illustrate various forms preventing it. of switch wherein my invention is employed, 8Q The term are as used in the preceding and which may therefore be used with safety paragraph is intended to comprise only that whatever the relation of current phase to popersistent and self-supporting flame whichis tential phase. Fig. 5 is a plan view of a formed in ordinary cases upon rupture of switch for throwing one or the other of two heavy currents. Where my switch is used generators into circuit with a given set of 85 3 5 there isasputtering spark which passes across translating devices. Figs. 6 and 7 are an elethe gaps of the switch, but it is more in the vation and plan respectively of a form of nature of a lightning spark than of an arc, switch wherein my invention is embodied in and therefore there is no error in speaking of an auxiliary device attached to an ordinary my device as calculated to prevent an arc, switch, and Fig. 8 is a plan of a modified form 90 4o meaning the type of are which is self-supportof switch.

ing, and is already well known in connection In considering the accompanyingdrawings, with dynamo currents. The spark caused on 1 and 2 represent the mains from which ouruse of my switch is not persistent, and leaps rent is supplied to the switch in question, and

rather than spans the gap. 3 represents the translating devices which are 5 It has been discovered that, where alternatfed through said switch.

ing current circuits are interrupted by means Considering Fig. 1, the translating devices of a break or breaks between parts composed are brought into circuit by bridging between of so called non-arcing metal, such as zinc the parts 5 and 6, and 7 and S, by means of or drawn brass, no arc will be formed where the parts a on each side of the swinging arm, 10c. the electromotive force and current are in If these parts are made of non-arcing metal phase with each other. The number of gaps such as zinc or drawn brass, and the current to be interrupted is of such a nature that the electromotive force is in phase with the current, no arc will be formed upon opening the switch, as it is found in practice that this metal refuses to carry an alternating are under these circumstances. If, however, the electro-i'notive force and current in the circuit to be ruptured be not in step, or nearly so, the rupture of the circuit by such a device as is shown in Fig. 1 will be attended by the formation of a long and dangerous are. As this condition of difference of phase between the current and electromotive force of a circuit is universal where self-induction de- Vices are present, it is evident that it is important to find some means, other than nonarcing metal alone, whereby this arcing may be prevented. One form of a switch which will accomplish this end is shown in Fig. 2, where the cylinders 9 are made of non-arcing metal, provided with strips of non-arcing metal 10. A number of breaks in the feeding circuit of the devices 3 is thus formed, and the similarly constructed cylinders 11 and strips 12 are mounted upon the movable handle 13 for the purpose of bridging these gaps when the circuit is to be completed. Around one or more of the gaps in the stationary part of this switch is placed a shunt 14E of high resistance, which should bein non-inductive form. I have found that the resistance necessary decreases in amount as the amperage of the current to be interrupted increases. A switch constructed as shown in this figure will safely break an alternating current wherein the electromotive force and current differ in phase approximately ninety degrees. I have also found that a condenser placed in shunt in the place of this resistance has the same effect, but that the capacity of the condenser necessary increases with the amperage of the current to be broken. The capacity of condenser necessary in this connection is trifling. I have shown this modification in Figs. 5 and 8.

The resistance used by me in the shunt cir cuit is such as is adapted to counteract the rent wave is in phase with the wave of eleci tro-motive force. The latter class of current can be safely interrupted by non-arcing metal alone, whereas my invention is necessary to be used where a lag exists. Of course the amount of resistance employed differs with the amount of lag, the frequency of alternation, and with the various metals employed in the switch; some metals being non-arcing for low currents which are not so for greater ones; but in any event the amount of current which passes through my shunt at any time is comparatively nothing, and is certainly in appreciable, particularly as the shunt and the main circuit are in nearly all cases broken simultaneously. It Will also be noticed that, in all cases, both terminals of my shunt are connected with parts of the switch which are directly in the main circuit as long as any current at all is passing.

Another form of switch is shown in Fig. 3, where the non-arcing rotatable rollers 15 are used in connection with the bridging plates 10 on the handle 17, in an obvious manner. By the use of the shunt 14, as shown in this figure, all arcing upon rupture of the circuit is avoided. The shunt is not necessarily placed around one or more of the stationary contacts, but may exist between a stationary and a movable contact as shown in Fig. t at 14. Of course the case of a shunt around one or more of the movable gaps would be merely an inversion of the case shown in Fig. 2, as it matters not in this form of switch which memher is movable.

So quick and certain is the action of my form of switch in the interruption of current, that it may be used to throw lights from one alternating generator to another with such rapidity as scarcely to cause a wink in the lights. In Fig. 5 is shown a switch intended for this purpose. Here the bars 18 are connected permanently with the terminals of the translating circuit, and are adapted, by contact with the terminals 19 or 20 of one or the other dynamos 21 and 22, to carry current to the lights or other translating devices 23. Two breaks are thus produced in each circuit, and around one of said breaks on each side is situated a device for counteracting the effect of lag in producing an arc. These devices may one or both consist of a condenser, or one or both maybe a resistance. Both forms of lag compensating devices are indicated in this figure. It is evident that by a rapid movement of the bars 18 in one direction or the other, one or the other generator may be thrown out of circuit, the other being cut into circuit. If any are were formed, this could not of course be accomplished, as the formation of the are following the bar, would form a connection between the two generators which would be disastrous.

It is to be understood that in all the above described cases the contact parts or some of them are composed of non-arcing metal.

In the form of switch shown in Figs. 6 and 7, the non-arcing arrangement is in the form of an attachment to the main switch, and none of the parts of the latter need in this case be made of non-arcing metal. Here a row of non-arcing metal cylinders 2 1 are placed in shunt around the contacts 25 and 20, as shown, and these cylinders are provided with the necessary resistance or capacity lt, as shown. In this form of switch the parts are so arranged that the break occurs, first, between one of the main movable contacts; secondly, at the nonarcing cylinders, and, lastly, at the second pair of main contacts. This is accomplished in the form shown by shortening the contact 27, and by lengthening the contacts 28 which are destined to bridge the gaps between the cylinders. Of course this might be accomplished in any other desired manner. By the use of a switch of this character very large currents having a great lag of current phase may be broken with safety.

In Fig. 8 I have indicated a modified arrangement of switch, or circuit breaker, wherein two overlapping shunts, 29 and 30, are shown. These have been shown as respectively a resistance and a condenser, but evidently the same kind of device may be used in both shunts if desired, or the position shown may be inverted, without departing from the spirit of my invention.

In the specific form shown, two of the cylinders are split and their halves are capable of being moved into contact with adjacent cylinders by means of wedges 31 capable of insertion into apertures 32.

I do not limit myself to the exact details herein shown and described, as many mechanical changes may be made without departing from the spirit of my invention.

hat I claim is 1. In a circuit interrupting device, containing a number of points of circuit interruption, a shunt around one or more of said points of interruption, and a device in said shunt tending to counteract the eifect of current lag in producing an are, substantially as described.

2. In a circuit-interrupting device, contain ing a number of points of circuit interruption, a shunt around one or more of said points of interruption, and a resistance in said shunt so proportioned as to counteract the effect of current lag in producing an are, substantially as described.

3. In a circuit interrupting device, a number of stationary contacts, and a number of movable contacts, some or all of said contacts being made of non-arcing metal, in combination with a shunt around one or more of said contacts, and a device in said shunt for counteracting the arcing effect of a lag in the current interrupted, substantially as described.

4.. In a circuit-interrupting device, a number of stationary contacts, and a number of movable contacts, some or all of said contacts being made of non-arcing metal, in combination with a shunt around one or more of said contacts, and a resistance in said shunt so proportioned as to counteract the effect of current lag in producing an arc, substantially as described.

5. In a circuit interrupting device, a number of non-arcing metal cylinders having gaps between them adapted to be bridged for the completion of a circuit, in combination with a shunt around one or more of said gaps,and a device in said shunt for counteracting the arcing eifect of lag in the current to be interrupted, substantially as described.

6. In a circuit interrupting device, a number of stationary contacts, a number of movable contacts adapted to bridge the spaces between said stationary contacts simultaneously, a shunt around one or more of said contacts, and a device in said shunt tending to counteract the effect of current lag in producing an are substantially as described.

7. In a circuit-interrupting device, containing at least four points of contact, overlapping shunts around diiferent sets of gaps between such points of contact, and devices in said shunts for counteracting the arcing effects of lag in the current to be broken, substantially as described.

8. In a circuit-interrupting device, a number of stationary contacts always in circuit as long as any current flows and a high resistance shunt having its terminals connected to two of said contacts, substantially as described.

9. In a circuitinterrupter,a numberof stationary contacts and a number of movable contacts adapted to bridge the gaps between the said contacts; in combination with a main circuit including a number of said contacts, and a high resistance shunt including one or more of said contacts not included in said main circuit, substantially as described.

In testimony whereof I have hereunto subscribed my name this 24th day of February A. D. 1894:.

HENRY NOEL POTTER.

WVitnesses:

JAMES WM. SMITH, HUBERT O. TENER. 

